Worried who you can trust for your Home Improvements?
We have the solution so you can relax and get on with your life

Home Extensions

Please find 20 things that our Accredited contractors know all about so you no need to worry!!

1. The ‘Right to Light’ Exists in Law

Neighbours may attempt to oppose your plans to Extend by claiming they have a legal right to light to one or more of their windows. There is such a thing as a legally established ‘right to light’, usually established automatically ‘by prescription’ after 20 years, however, it is only relevant in limited circumstances.

A right to light is a type of easement and overrides any planning permission you might have and your permitted development rights. It can in theory, therefore, prevent you from blocking out a neighbour’s window. However, it only provides for whatever light is reasonably required for the use of the building. It does not mean that your extension cannot obstruct a neighbour’s window or view, or reduce the amount of sunlight entering – these are planning considerations. Rights of light are only likely to be relevant in Town Centres where buildings are very close together. In such circumstances, it may be prudent that the Architect contact a specialist solicitor.

2. You Can Have WCs and Shower Rooms Anywhere

It used to be a requirement of the Building Regulations for there to be a lobby between a WC and any other room. This was commonly conceived to be for reasons of hygiene and to relate to the kitchen where food is prepared. Although it is desirable for reasons of privacy to locate WC facilities off hallways, circulation space, lobbies or the utility room, this is no longer necessary under the Building Regulations. It is, however, necessary for there to be a wash basin and suitable ventilation to all WCs. You can also put a shower room anywhere that has enough space. A basic shower room need measure only 900mm wide by 1.8m (or 2.6m if it is to include a WC and basin).

3. Minimum Ceiling Heights

Although the legal minimum ceiling height has now been removed from the Building Regulations, there is still a practical minimum height and this is especially worth thinking about in attic and cellar conversions. All rooms should normally have a floor to ceiling height of at least 2.1m throughout (standard ceiling height is 2.4m). In rooms with sloping ceilings, at least 50% of the floor area should normally have a floor to ceiling height of at least 2.1m.

4. Site Insurance

Many people don’t know that most home insurance providers will not cover the building if you are changing the structure of the build. For example, extending, doing a conversion or renovation. When carrying out the works you need to have site insurance with an Accredited insurer to cover the existing structure and the new works until complete. Building Contractors will often say they have Public Liability insurance but it is important to check their documents as the majority have just liability cover which will require you to prove fault in the event of a claim, which can mean a lengthy legal battle. This may also not cover any natural events claims, such as fire, flood and storm damage. So, by taking out your own Site Insurance you are safe in the knowledge you are protected.

If you are vacating the property during the build, you will require site insurance or unoccupied buildings insurance which will usually be a minimum six-month policy. Always contact your existing insurance provider to notify them of works before you start as well as shopping around for the best Policy.

5. Avoid Through Rooms

Working out the most efficient and practical way to access an extension is often the greatest design challenge. Do not sacrifice more than you are gaining, for instance by slicing up a good-sized bedroom to gain access to an extension that adds only one more bedroom of a similar size is totally false economy.

Using an existing room to access an extension rarely works unless it is sufficiently large and the furniture carefully arranged. Such rooms usually end up as nothing more than a corridor and a dumping ground for storage.

Circulation space is very important to the healthy function of a house, ensuring that it is liveable and that the best use is made from all the space. When extending, this may mean rethinking the function of every room in order that the principle rooms, most importantly the kitchen, dining and lounge space, can all be accessed directly from the main hallway.

In smaller houses where there is no space for a separate hallway, it is a good idea to have at least a small lobby or enclosed porch to create privacy from the front door.

6. Make Your Conservatory and Orangery Part of Your Home

You can integrate a conservatory or orangery into the existing house to make it an extension to an existing room, rather than an add on, but you must be very careful with the design.

The Building Regulations require most conservatories and orangeries to be separated from the existing house by exterior quality doors known as a barrier. Such a doorway with a threshold can leave the new space feeling isolated from the rest of the house and unless the conservatory is large enough to work as a room in its own capacity, (the minimum is around 3m x 4m) it can end up being an expensive, underused space. By seeking the correct planning permissions these structures are not then defined as portable structures and can become part and part of your home without the need of such barriers.

French or patio doors can be left open to help make a conservatory or orangery feel like part of the house, but even double glazed conservatories lose heat quickly and so most people end up closing their conservatory or orangery off for the winter months to help keep their home warm and their fuel bills down. Remember, a portable building must have a weather rated barrier.

With a bit of creative design to reduce the glazed area, the section of exterior wall separating it from the existing house can be completely removed. This turns the conservatory or orangery into a true extension, and by incorporating sections of plastered wall and insulated solid roof, a conservatory or orangery can be used to extend an existing room such as a dining room or kitchen and most importantly become part and part of your home.

To turn a conservatory or orangery into an extension you must provide your local building control department with calculations that show that the amount of glazing in the windows, doors and roof of the conservatory or orangery/extension, together with the amount of glazing in the windows, doors and any roof lights in the original house, do not exceed 25% of the floor area of the conservatory or orangery and all floors of the house added together.

New windows and doors in the conservatory or orangery/extension will need to meet the current U-values required by the Building Regulations.

7. Consider Adding Basement Space

If you have an existing cellar, you can convert it into living space without using up the volume allocated to you under permitted development rights. Creating basement windows and external access will not usually require planning permission either, although it is always worth checking your local authority’s policy on basements. All work must, however, comply with the Building Regulations laid out in the Approved Document – Basements for Dwellings 2000 (www.basements.org.uk).

Converting existing cellar space to bring it up to habitable standards costs from £1,500-1,750/m² providing there is already enough headroom. Creating a new basement beneath an existing building to add extra space is also possible. The cost is £3,000-4,000/m². Due to the cost, it is usually only financially viable to retrospectively add a basement in high value areas such as Central London.

8. Balance Your Accommodation

Although there are no legal requirements to provide more than one bathroom, it is practical to have a least one full bathroom on the same floor as the main bedrooms. For larger households, it helps to have at least one en-suite preferably off of the master bedroom.

If you are extending to add extra bed­rooms, clearly creating the number of bedrooms needed for the household is the main priority, but this should, if possible, be balanced by an increase in the number of bathrooms. Future purchasers will expect at least one bathroom and a shower room on a four or five-bedroom house and without this the value will be constrained and the improvements not prove in the future to have been planned as well as they might have been.

9. Know the Building Regulations for Extensions

Even if you do not need planning permission for your extension, because you are using permitted development rights, you must get building regulation approval.

The Building Regulations set out minimum requirements for structural integrity, fire safety, energy efficiency, damp proofing, ventilation and other key aspects that ensure a building is safe.

Most repair work is excluded from the Building Regulations, with the exceptions of replacement windows, underpinning and rewiring. However, apart from certain new buildings such as sheds, outbuildings and some conservatories or orangeries, all new building work, including alterations, must comply with the Building Regulations.

Here is a list of examples

  • Home extensions such as for a kitchen, bedroom, lounge, etc.
  • Loft conversions. Internal structural alterations, such as the removal of a load-bearing wall.
  • Installation of baths, showers, WCs which involve new drainage or waste plumbing.
  • Installation of new heating appliances.
  • New chimneys or flues.
  • Altered openings for new windows.

10. You Can Start Within 48 Hours of Notifying Building Control

Once you have dealt with planning, if you are in a hurry to start extending, you can commence work immediately after giving the local authority building control department 48 hours’ notice. You are required to submit a ‘Building Notice’ and the required fee. Building control will then have on record your project has commenced.

Generally, the Buildng Notice method is more suitable for simple works where detailed drawings are not required, but it can be used for any project, except for work to listed buildings. Some of our accredited contractors use the services of private building control companies that are usually ex building inspectors and they have full rights to inspect each aspect of the build and will get signed off. They will also ensure the process is compliant and up to building control standard.

For most extensions, it is best to make a Full Planning application. This involves submitting detailed drawings, specifications, calculations and a location plan for inspection by the local authority, together with the application forms and appropriate fee.

Building control has to respond within five weeks unless you agree to give them an extension to two months. A Full Planning submission allows any irregularities to be resolved before work commences.

With a Building Notice, the building control officers can ask for proof of compliance at any stage, so it is essential to make sure they make all necessary inspections and provide any structural calculations when requested. When the project is completed and inspected by the local authority, a completion certificate will be issued which will prove useful if the property is ever to be sold on.

11. What About Removing Your Walls?

You don’t need walls to define rooms. Creating larger, more open spaces by knocking down walls will help to make a properly feel larger. The fewer walls you use, the more spacious and light a property will feel. This applies whether you are extending your home or just re-designing instead.

You can define separate rooms and functions by using all sorts of other features such as furniture, lighting, floor coverings, decoration, floor or ceiling levels, and informal room dividers such as kitchen island or peninsula units, fire­places, open shelving, island walls or even the stair­case.

If you are unsure whether it will work, visit show houses built by developers. Most now feature at least an open plan kitchen breakfast space instead of a separate kitchen and dining room.

12. There are Different Rules for Extending in Conservation Areas

If you live in a Conservation Area your Permitted Development rights conservatories, orangeries and extensions as well as alterations that do not require planning permission are restricted. Each local authority has its own policy for Conservation Areas but generally the basis of the policy is to prevent the loss of character of the respective Conservation Area. So, if you are thinking about extending your home, always contact your local conservation officer first to discuss the matter or ask your architect to pursue.

Please remember, planning permission is required for the addition of dormer windows or any other change to the shape or height of the existing roof, including the addition of Velux roof lights if they face the highway. This means that attic conversions will almost always require planning permission in a Conservation Area.

13. Have You Really Thought Through Your Loft Conversion?

Before thinking about an expensive attic conversion look carefully into the cost relative to the amount of useful space that can be gained, and the impact on the existing accommodation. In order to comply with the Building Regulations to form an additional bedroom in the roof space, the floor may need strengthening and the roof will need to have at least 150mm of insulation, plus a 50mm clear air gap, unless you are able to replace the existing roofing felt with a breathable membrane.

The result of bringing the loft space up to habitable requirements is that the ceiling height will typically be lowered by 60-100mm and the floor level raised by at least 15-20mm. Both changes will reduce the amount of usable space with good headroom. If steel purlins or joists need to be added, too, this can further reduce the space you end up with.

If the usable space is limited, consider raising the roof height by rebuilding it, or even lowering the existing ceiling height below. Accessing a habitable loft conversion requires a permanent staircase and this will also need landing space.

If you decide the cost of a full loft conversion cannot be justified because of space constraints, consider improving the loft space to create storage accessed by a fold-away loft ladder or space-saver stair­case? This can be achieved at a significantly lower cost than a full conversion. Attic conversions cost from £800/m² for a simple conversion, up to £1,850/m² for more complicated design.

14. Extending a Listed Building Can Be Problematic

Permitted development rights do not apply to listed buildings, so any extensions will need both planning and listed building consent. The design of any extensions to a listed building need to be of a very high quality and it will be necessary to use the services of a specialist architect, surveyor and most importantly a project manager.

It will be essential to work closely with the local authority conservation officer if you are extending your home. Each officer will have their own perspective on what will alter the character of a listed building. It is a criminal offence to alter a listed building, inside or out, without listed building consent.

15. Permitted Development is Not Always Straightforward

Under the new rules, the ‘original’ (as it stood in or prior to 1948) rear wall of a detached home can be extended by up to 8m in depth with a single storey extension; this is reduced to 6m if you are extending a semi-detached home or terrace. If your proposed new extension will be within 3m of a boundary, then the eaves height is limited to 2m under Permitted Development.

If you hope to build a two-storey extension (no higher than the house), this can project up to 3m from the original rear wall, so long as it is at least 7m from the rear boundary. It’s also important to note that no extension can project beyond or be added to what is deemed to be the front of the house or an elevation which affronts the highway. A side extension cannot make up more than half your house’s width.

Furthermore, except for some conservatories and orangeries, new extensions must be built of materials ‘similar in appearance’ and with the same roof pitch as the main house. So, while Permitted Development rights are beneficial, there’s a lot to consider before extending.

Prior to the new legislation, volume limitations were applied to the entire house, so if you were extending, you were unlikely to be able to convert your loft under Permitted Development rights as well. The good news is that the latter has now been separated out, allowing you to undertake both without one restricting the other. When you are extending your home, you can also convert your loft into a bedroom or extra living space by up to 50m³ in a detached house, or by 40m³ within any other home.

16. Minimum Room Sizes

It can be tempting to try to subdivide existing and new space into as many bedrooms as required, particularly if budget or the size of the extension permitted is restricted. However, there are minimum sizes beyond which rooms will not function.

When considering applications for conversions, most local authorities have recommended minimum room sizes which planning applications must conform to. However, the rules about sizes are more applicable to social housing and are usually relaxed for private accommodation, but you should still bear them in mind if you are extending.

Function of room Minimum Size
Double bedroom 10.2-11.2m²
Single bedroom 6.5-8.4m²
Living room 13-13.2m²
Dining room 9.5m²
Kitchen 7.2-7.65m²
Kitchen/diner 12m²
Lounge/diner 15-18m²
Bathroom and WC 3.6m²
Bathroom only 2.8m² (or 1m² of circ.)
WC only 1.3m²
Hallways and landings 900mm width

In addition, rooms must always have external windows, except for non-habitable rooms such as kitchens, bathrooms, dining rooms and studies.

17. Know the Party Wall Act

Your neighbours cannot stop you from building up to, or even on, the boundary between your properties, even if it requires access onto their land (providing you have planning permission to do so, and there are no restrictive covenants).The Party Wall Act etc. 1996 allows you to carry out work on, or up to, your neighbours’ land and buildings, formalising the arrangements while also protecting everyone’s interests. This is not a matter covered by planning or building control.

If your extension involves building or digging foundations within 3m of the boundary, party wall or party wall structure, or digging foundations within 6m of a boundary, the work will require you to comply with the Party Wall Act. In these cases, you may need an architect or surveyor to act on your behalf. The act does not apply in Scotland.

18. There is a Difference Between an Estimate and a Quotation

An estimate is normally a contractor’s guess as to what your extension will cost. Whether given verbally, or in writing, is not legally binding and the final bill may exceed it.

A fixed price quotation based on and including a schedule of works is a definite price. When deciding which builder to choose, always get written quotations from at least two firms, ideally ones that have been recommended to you. Extra costs will be requested if ground works require alterations in depth and or design or subsequently you request additional works and or materials where additional labour charges will also be levied. As a rule of thumb to ensure you have allowed within the budget an additional 15/20% to complete the project to your standard as budgets are sometimes not allowed for in conjunction to flooring, decoration and furniture.

All written quotes should itemise the work to be done, provide a breakdown of costs and a total, and state whether VAT is included. When you receive the offers, check whether there are any caveats which might involve extra expense. Also, compare provisional sums for work such as foundations to make sure you are comparing like with like. Therefore, a schedule of works from each contractor is the easiest comparison.

19. Beware of Removing Trees

Some trees are protected by Tree Preservation Orders. Even if an extension does not require planning permission you cannot alter or even prune a tree that has a TPO on it without planning permission.

All trees within a Conservation Area are protected by legislation and effectively have a TPO on them providing they have a trunk of diameter greater than 75mm. Altering a tree that is protected by a TPO is a criminal offence and can result in substantial fines so take care if you are extending your home near to a protected tree.

20. You Probably Can’t Claim VAT Relief if You Are Extending

Most extensions will be subject to VAT on labour and materials at the standard rate of 20%, especially if you use a contractor to undertake the work. If you use local tradesmen who are not VAT registered you can save the 20% VAT on their labour, but you will still have to pay VAT on materials at the standard rate. Some extension projects are eligible for VAT relief, such as work to listed buildings (zero rated), the conversion of an existing dwelling that changes the number of units (reduced rate of 5%) and work to a building that has been unoccupied for at least two years (reduced rate of 5%).

To benefit from VAT relief if you are extending a listed building or renovating an unoccupied home, you must use a VAT registered builder — you cannot reclaim the VAT yourself.

For more details & information, please register your enquiry now!

For more details & informationRegister your enquiry now!